Acrylic bone cement is currently the predominant synthetic biomaterial used for anchoring the prosthesis to the contiguous bone in a cemented arthroplasty. In these joint replacements, the cement mantle should, among other things, allow the transfer of body weight and service loads from the prosthesis to the bone and/or increase the load-carrying capacity of the prosthesis-bone cement-bone system. It is well recognized, however, that the bone cement mantle often experiences fatigue fracture - due to the propagation of cracks that emanate from, for example, entrapped air bubbles, blood inclusion, etc. - which may ultimately lead to aseptic loosening of the prosthesis. The goal of the proposed exploratory project is to develop and examine the feasibility of using autonomous agents in acrylic bone cement composites. Autonomous agents, sometimes referred to as self-healing materials, possess the ability to heal cracks autonomically and, hence, recover the structural function of the component. It is the hypothesis of the proposed work that the incorporation of autonomous agents into an acrylic bone cement matrix will increase the cement's fracture toughness and fatigue life significantly, while markedly decreasing the rate of propagation of cracks through it. Accordingly, the specific aims of the proposed research are to (1) incorporate autonomous agents into acrylic bone cement (to obtain self-healing bone cement composites), (2) develop new self-healing chemistries for acrylic bone cements, and (3) determine the mechanical properties of these composites. The joint integration of the three specific aims will provide the groundwork for a new group of acrylic bone cement composites. More importantly, successful achievement of the goal of this developmental project will significantly increase the in vivo longevity of cemented joint replacements which will, in turn, translate to increased patient satisfaction and decreased hospital costs. The collaborative project will also create opportunities for women and underrepresented minority students to participate actively in the fields of synthetic polymer chemistry, biomechanical engineering and biomaterial research.